1. Field of the Invention
The present invention is related to a printed matter on which thin film is formed by a printing method. The present invention is related to a method to form functional organic thin film on a substrate sectioned by partition wall in particular. Above all, the present invention is related to an organic electroluminescent device used for display units such as information display terminal or plane emission light source.
2. Description of the Related Art
In late years optical display units of various sizes are used as a display unit of information display terminal.
Above-all, display unit with the use of organic electroluminescent device is self-luminous type. Therefore, as for the organic electroluminescent device, speed of response is fast, and, in addition, power consumption is low. Therefore, organic electroluminescent device attracts attention as a display unit of the next generation.
Configuration of organic electroluminescent device is the configuration which luminous layer including organic luminescent material was sandwiched between a first electrode and a secondary electrode. When voltage is applied between these electrodes, hole poured by one electrode and electron poured by the other electrode couple again in luminous layer. Light occurring in this case is used as image display or light source.
On/off adjustment of luminescence of each pixel is necessary to display an image using organic electroluminescent device. Therefore it is necessary for electrode on one side to be form of pattern. Usually, for example, a first electrode formed on a substrate is etched. There is step in an end of pattern-shaped first electrode on a substrate. Organic luminescence media layer such as a hole transport layer or luminous layer on first electrode cannot completely cover this step. So this configuration may cause a short circuit. Therefore an end of first electrode should be covered by an insulating material. In addition, inks on neighboring pixels are mixed or are connected when a hole transport layer and a luminous layer on first electrode are formed by using liquid ink by means of a method to discharge ink from nozzle or a printing method. Partition wall should be formed to prevent this phenomenon. Thus, along each first electrode, partition wall is formed. Shape of partition wall of organic electroluminescent device of passive type is stripe shape. Partition wall of organic electroluminescent device of active type is lattice-shaped. (Japanese Patent Laid-Open No. 11-810862 Official Gazette).
Ink is hard to be scattered in the method that ink is filled between partition walls by printing, in comparison with a method to supply ink from nozzle. Therefore, in the method that ink is filled between partition walls by printing, partition walls may be low. However, in a printing method, if printing plate having pattern does not correspond with a substrate one-on-one, printing cannot be performed. In addition, aligning is necessary, too.